3  Sources of Relevant Data

This Chapter provides an broad overview over relevant available data sources. All these data can be accessed via download from the web free of charge except where otherwise mentioned.

The Chapters Chapter 4, Chapter 5, Chapter 6 and Chapter 7 describe in detail how these data can be prepared for hydrological modeling with RSMinerve. Prior to this, the following Section 3.1 provides an in-depth discussion of the derivation of a consistent set of gauge location data.

3.1 Gauge Location & Norm Discharge Data

The Central Asia Hydrometeorological Organizations are the organizations administering discharge data. Unfortunately, the organizations do not have a good understanding of most of the past and current locations where they monitor this discharge. This can be verified by checking the website Hydrometeorological Services in Central Asia where many of the shown gauges are not correctly georeferenced.

This is problematic for many reasons and especially also for GIS-analysis and hydrological modeling. With a focus on the mountain rivers, we developed a workflow to verify gauge locations communicated by Hydrometeorological Organizations in a consistent and comprehensive manner. With the goal to establish a comprehensive archive, this workflow was applied to map operational stations and past stations.

First, data from all existing gauges and locations were entered in a dataframe with the following attributes:

• CODE: Official gauge code in use
• EASTING and NORTHING: Coordinates in UTM42N
• LON and LAT: Longitude and latitude
• NAME_ENG: Translated english station name
• NAME_RU: Original station name
• RIVER: Name of river
• BASIN: Name of larger basin
• COUNTRY: The country the gauge is located in
• Q_NORM_M3S: Long-term norm discharge
• OBS_PERIOD: Observation period of long-term norm discharge
• SOURCE: Source of information on norm discharge

Second, data on historic stations were obtained from the Soviet compendia Surface Water Resources, Vol 14 Issues 1 and 3. Third, data from northern Afghan rivers’ stream flow characteristics and the location of gauging stations there were obtained from (Olson and Williams-Sether 2010). Norm discharge was calculated from the available data.

All stations were manually located in a Geographic Information System (GIS) using the relevant Soviet Military Topographic maps (1:200’000) from the corresponding region. The maps were downloaded from https://maps.vlasenko.net and subsequently georeferenced in QGIS with the Raster/Georeferencr tool there (QGIS Development Team 2021). Where possible, high-resolution satellite imagery from Microsoft® Bing™ Maps was finally used to identify measurement bridges and for a final validation of the identified locations.

The upstream catchments for each gauge were then mapped in R using the WhiteboxTools v.2.0.0. Like this, we have compiled a list of 297 gauges with their contributing catchments. Figure 3.1 shows the result.